Two series of experiments emphasize learning by human subjects of physiological reactions basic to emotional experience. Cognitive- perceptual evaluations of contingencies among stimulus events are stressed. The first series of investigations develops the concept of expectancy as it relates to learned changes in anticipatory arousal preceding signaled stress and arousal to the signaled event itself. Predictive certainty and verbal associations are manipulated and observations are made on evoked EEGs and autonomic responses. Confirmation of cognitive expectancy is also manipulated. The second group of experiments evaluates learned inhibition of autonomic responses by empirical arrangements which vary the degree of negative contingency between warning signals and stress and by related procedures involving learned relaxation of skletal muscle tension.